1. Field of the Invention
This invention pertains to mixers for food products.
2. Description of the Prior Art
A conventional mixer may have a varying tub size that will handle 750 lbs. to 10,000 lbs. of preferably ground meat. The mixer is normally filled from above with the product by means of a conveyor or similar equipment. Inasmuch as a definite period of time may be required for complete mixing, two counter-rotating shafts having agitators thereon may be utilized. The shafts may have similar pitch paddles located thereon which will also cause the product to move longitudinally in the tub driven by the paddles of one shaft and returned by the other, thus continuously recirculating same. Frequently the paddles overlap for better mixing between the shafts. Normally a drive for the counter-rotating paddles is located at one end of the tub and movable discharge doors at the other end. Also associated with mixers of this type may be top covers for vacuumizing the food or CO.sub.2 or steam injection. The discharge doors may be operated manually or remotely by suitable actuating means. Of course, easy cleanup must be possible with these batch type mixers.
For good mixing and economy of construction it is customary to make each shaft and its agitators, which may be paddles or ribbons or combinations thereof, the same and rely on the counter-rotating shafts to secure the internal circulation. Also, if paddles, they are usually mounted on spokes attached to each shaft along a right hand helix with each mixing paddle having a left hand pitch at about 45.degree. to the centerline of the shaft. Due to a preferable over-lap between the paddles of each shaft, a very good mixing action is obtained. Suitable paddle arrangements at each end of the tub aid in internal circulation. To discharge the product, usually the end opposite the drive is movable for the shafts and agitators to discharge the product. Some tubs tilt 90.degree. to discharge but usually further cleaning is needed. Also bottom discharges have been used but without much success. While the above described devices have mixed the product fairly well, the discharge time has been unduly lengthy resulting in substantial "down time" of the mixer.